01 welcome to itrc’s internet training – “systematic ...welcome to itrc’s internet training...

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0Welcome to ITRC’s Internet Training –“Systematic Approach to In Situ Bioremediation”

Thank you for joining us. Today’s training focuses on the ITRC Technical and Regulatory Guidance Document entitled:“ Systematic Approach to In Situ Bioremediation in

Groundwater: including Decision Trees on Nitrate, Carbon Tetrachloride and Perchlorate”

The training is sponsored by: ITRC & EPA-TIO

Creating Tools & Strategies to Reduce Technical & Regulatory Barriers for the

Deployment of Innovative Environmental Technologies

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Presentation Overview:This course presents a decision tree for reviewing, planning, evaluating, and approving in situbioremediation (ISB) systems in the saturated subsurface. It defines site parameters and appropriate ranges of criteria necessary for characterization, testing, design and monitoring of ISB technologies. Contaminants and breakdown products differ, however, many characteristics of a site used to determine the efficacy of ISB, are similar. Once a site has been characterized for ISB efficacy and the contaminants of concern and degradation products have been defined, engineered approaches can be designed, pilot tested and possibly deployed. Similarly, several aspects of ISB are characteristic of all sites, no matter what contaminant is being scrutinized. This training is based on the ITRC document entitled: “Systematic Approach to In Situ Bioremediation: Nitrates, Carbon Tetrachloride & Perchlorate.” The document: (1) describes what information is needed for any ISB evaluation; (2) provides a flow diagram that defines the primary decision points; (3) provides characteristics used to evaluate monitored natural attenuation or enhanced ISB application as remediation options. Examples of how to apply this document, including respective decision trees, for nitrate, carbon tetrachloride, and perchlorate are included.

ITRC – Interstate Technology and Regulatory Council (www.itrcweb.org)EPA-TIO – Environmental Protection Agency – Technology Innovation Office (www.clu-in.org)ITRC Course Moderator:Mary Yelken - ITRC – [email protected]

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1ITRC – Shaping the Future of

Regulatory Acceptance

Natural AttenuationEISB (Enhanced In Situ Bioremediation)Permeable Reactive Barriers (basic and advanced)Diffusion SamplersPhytotechnologiesISCO (In Situ Chemical Oxidation)Systematic Approach to In Situ Bioremediation

ITRC Member State

Federal Partners

Sponsors

Industry, Academia, Consultants,Citizen Stakeholders

ITRC Membership

States

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The bulleted items are a list of ITRC Internet Training topics – go to www.itrcweb.org and click on “internet training” for details.The Interstate Technology and Regulatory Council (ITRC) is a state-led coalition of regulators, industry experts, citizen stakeholders, academia, and federal partners that work to achieve regulatory acceptance of environmental technologies. ITRC consists of 40 states (and the District of Columbia) that work to break down barriers and reduce compliance costs, making it easier to use new technologies and helping states maximize resources. ITRC brings together a diverse mix of environmental experts and stakeholders from both the public and private sectors to broaden and deepen technical knowledge and streamline the regulation of environmental technologies. Together, we’re building the environmental community’s ability to expedite quality decision-making while protecting human health and the environment. With our network approaching 6,000 people from all aspects of the environmental community, ITRC is a unique catalyst for dialogue between regulators and the regulated community.ITRC originated in 1995 from a previous initiative by the Western Governors’ Association (WGA). In January 1999, it affiliated with the Environmental Research Institute of the States, ERIS is a 501(c)3 nonprofit educational subsidiary of the Environmental Council of States (ECOS). ITRC receives regional support from WGA and the Southern States Energy Board (SSEB) and financial support from the U.S. Department of Energy, the U.S. Department of Defense, and the U.S. Environmental Protection Agency.

To access a list of ITRC State Point of Contacts (POCs) and general ITRC information go to www.itrcweb.org.

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ITRC Disclaimer and CopyrightAlthough the information in this ITRC training is believed to be reliable and accurate, the training and all material set forth within are provided without warranties of any kind, either express or implied, including but not limited to warranties of the accuracy, currency, or completeness of information contained in the training or the suitability of the information contained in the training for any particular purpose. ITRC recommends consulting applicable standards, laws, regulations, suppliers of materials, and material safety data sheets for information concerning safety and health risks and precautions and compliance with then-applicable laws and regulations. ECOS, ERIS, and ITRC shall not be liable for any direct, indirect, incidental, special, consequential, or punitive damages arising out of the use of any information, apparatus, method, or process discussed in ITRC training, including claims for damages arising out of any conflict between this the training and any laws, regulations, and/or ordinances. ECOS, ERIS, and ITRC do not endorse or recommend the use of, nor do they attempt to determine the merits of, any specific technology or technology provider through ITRC training or publication of g u i d a n c e d o c u m e n t s o r a n y o t h e r I T R C d o c u m e n t .

Copyright 2007 Interstate Technology & Regulatory Council, 444 North Capitol Street, NW, Suite 445, Washington, DC 20001

Here’s the lawyer’s fine print. I’ll let you read it yourself, but what it says briefly is:•We try to be as accurate and reliable as possible, but we do not warrantee this material.•How you use it is your responsibility, not ours.•We recommend you check with the local and state laws and experts. •Although we discuss various technologies, processes, and vendor’s products, we are not endorsing any of them.•Finally, if you want to use ITRC information, you should ask our permission.

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3Systematic Approach to In Situ Bioremediation in Groundwater: Including Decision Trees on Nitrate, Carbon Tetrachloride & Perchlorate

What You Will Learn……….Essentials for understanding In Situ BioremediationSystematic evaluation for ISB for treatment of particular Contaminants of ConcernImportant elements of site characterization Contaminant characteristics & degradation pathwaysApplication of ISB for treating carbon tet., nitrate and perchlorateFeasibilityAdvantages & LimitationsDecision Tree Approach to BioremediationRegulatory Issues

Logistical RemindersPhone Audience• Keep phone on mute• * 6 to mute your phone and

again to un-mute• Do NOT put call on hold

Simulcast Audience

• Use at top of each slide to submit questions

Course Time = 2 ¼ hours

2 Question & Answer Periods

Links to Additional Resources

Your Feedback

No Associated Notes

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Meet the ITRC Instructors

Bart Faris, HydrogeologistRemediation Oversight Section, Groundwater Quality Bureau,New Mexico Environment Dept4131 Montgomery, N.E.Albuquerque, NM [email protected]

Dr. Eric Nuttall, ProfessorDept. Of Chemical and Nuclear engineeringUniversity of New Mexico221 Farris Engineering CenterAlbuquerque, NM [email protected]

Dr. Dimitrios VlassopoulosS. S. Papadopulos & Associates, Inc.7944 Wisconsin AvenueBethesda, Maryland [email protected]

Dr. Ron Buchanan, JrDupont Corporate Remediation

GroupBarley Mill Plaza 27Wilmington, De 19880Tel [email protected]

Bart Faris, is a hydrogeologist with the New Mexico Environment Department’s (NMED) Ground Water Quality Bureau. He is the project manager/regulator for multiple contamination sites throughout New Mexico dealing with numerous contaminants. He serves as NMED’s water representative for Border Issues with Mexico. Bart is the Interstate Technology Regulatory Council (ITRC) team leader for the In Situ Bioremediation team and was the team leader for the Enhanced In Situ Biodenitrification team. He is also a member of the Technical Advisory Group for the Innovative Treatment and Remediation Demonstration (ITRD) program at Oakridge National Laboratory Y-12 carbon tetrachloride (CT) project. Bart received his B.S in Soil and Water Science from the University of Arizona in 1983, and has published papers on in situ biodenitrification and monitored natural attenuation of CT. Bart has spent over 15 years in Latin America working with community’s water resources and agricultural production.Ronald J. Buchanan, Jr., Ph.D., is a Principal Consultant with DuPont Corp. Remediation Group in Wilmington, Delaware. Ron is a member of DuPont's Bioremediation Technology Network which is developing microbial anaerobic reductivedehalogenation and intrinsic bioremediation of chlorinated solvents. He is also a member of the EPA/RTDF Project Team developing and applying natural attenuation of chlorinated solvents at Dover Air Force Base in Delaware. Ron received his Ph.D. in Environmental Engineering and Science from Drexel University in 1977, and has published over two dozen papers in the field of hazardous waste management and environmental technology. He is a member of the Governor's Science Advisory Board in Pennsylvania and the Pa DEP Solid Waste Advisory Committee.Dimitri Vlassopoulos has been a geochemist with S.S. Papadopulos and Associates in Bethesda, Maryland for 10 years, where he conducts and supervises applied research in contaminant hydrology and in-situ groundwater remediation technologies. His areas of expertise include analysis of the environmental fate and transport of contaminants under natural andengineered conditions, development and application of computer simulation models, and environmental forensic techniques. He received a Ph.D. in environmental geochemistry from the University of Virginia (2000), an MS in Geochemistry from the California Institute of Technology (1993), and an MS in Geological Sciences (1989) from McGill University.H. Eric Nuttall, Ph.D., is a professor of Chemical/Nuclear Engineering at the University of New Mexico. Dr. Nuttall has over 200 publications/presentations and directs graduate student research on in situ bioremediaiton as well as teaches an annual course on bioremediation. Dr. Nuttall has developed and manages a very successful field site for in situ treatment of nitrate-contaminated groundwater. Dr. Nuttall is a member of the national Interstate Technology and Regulatory Council (ITRC) for in situ bioremedation, technology verification, and chemical oxidation. This group had produced several technical guidance documents on bioremedation. He also has developed an in situ process to immobilized uranium and heavy metals which is being tested both by DOE at an UMTRA site and in Germany through WISMUT.

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What is In Situ Bioremediation?

Bioremediation is the application of biological treatment to the cleanup of CoCs (Contaminants of Concern)• Microorganism• Hydrogeology• Chemistry• Engineering

Create subsurface environmental conditions conducive to the degradation of chemicals via microbial catalyzed biochemical reactions

CoCs = Contaminants of ConcernEngineered technique for optimizing subsurface conditions (hydrogeological, geochemical, microbial) to biodegrade contaminants in situ Includes injecting substrate and nutrients (i.e., amendments) Creates in situ conditions conducive to microbesMay include extracting and recirculating amended groundwaterEstablishes/accelerates contaminant biodegradation in situ

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6Systematic Approach to In SituBioremediation in Ground Water

Not a new Science

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Overview

First, Generic ISB Considerations

Second, Specifics

Third, Contaminants of Concern

• Nitrate – NO3 (Mature)

• Carbon Tetrachloride CCl4 (used but testing pathways is still underway)

• Perchlorate – ClO4- (Immature)

Finally, Bottom Line for ISB

No associated notes

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Key Issues

Guidance document for State & Federal regulators, RPs and consultant use of decision trees on ISB and contaminant chaptersInjection of amendmentsContaminant standardsState regulations equivalent to RCRA 3020(b)State UIC rules for injection of contaminated ground waterTechnical challenges

No Associated Notes

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Characterizing the Site

Refer to Figure 2-1 in the document

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Site Background

Site operational historyContaminant source & pervasivenessContaminant propertiesContaminant relationships

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Microorganisms

Microscopic organisms that have a natural capability to degrade, destroy or immobilize a wide range of organic and inorganic compoundsAccelerate microbial activity using nutrients• e.g. Phosphorus, Nitrogen

Food• e.g. molasses, vegetable oil, lactates, ethanol

Not a new science!

No associated notes

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Site Conceptual Model

DowngradientMonitoring

Wells~10 Drums ~6000 lbs

Porosity = 0.25Spill Zone

1000’

400’

Plume Boundary

1 ppmDissolved-phase

20 ‘

60 ‘ Flow1’/day

Clay Aquitard

No associated notes

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Hydrogeology & Transport

Define important parameters• Stratigraphy• Hydraulic Conductivity• Storativity• Groundwater Flow & Transport

Contaminant distribution• Type/mix• Advection & Dispersion• Retardation/Koc

Amendment delivery- including mixing• Type of System (passive, injection, recirculation)• Amendment Type• Amendment Delivery Rates

No associated notes

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Hydrogeology & Transport (Cont.)

CCl4

CHCl3

CH2Cl2

CH3ClCH4

No associated notes

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Chemistry

Kinetics

Stoichiometry

No associated notes

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Kinetics

Monod kinetics• Assumes cells growing

on the substrate are being degraded

First order• Rate is dependent solely

on the reactant under consideration

• dC/dT = - kC

Second order• Rate is simultaneously

dependent on two parameters (e.g., added substrate and contaminant)

Zero order• Rate is independent of

the reactant(s) under consideration

No associated notes

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Stoichiometry

Methanol

NO3- + 5/6 CH3OH → 1/2 N2 + 5/6 CO2 + 7/6 H2O + OH-

Ethanol

NO3- + 5/12 CH3CH2OH → 1/2 N2 + 5/6 CO2 + 3/4 H2O + OH-

Acetate

NO3- + 5/8 CH3 COO- → 1/2 N2 + 5/4 CO2 + 1/8 H2O + 13/8 OH-

No associated notes

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Transformation

Abiotic• Oxidation & Reduction reactions• Hydrolysis• Elimination• Volatilization

Biotic• Oxidation & Reduction reactions• Cometabolism• Assimilation• Sequential transformation

No associated notes

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Biological TransformationsChloroform

(CF)

Dichloromethane(DCM)

Chloromethane(CM)

Anaerobic Conditions

reductivedechlorination

Methane(CH4)



CO2, CO, CSO, CS2

acetate, formic acid

CO2

methanethiol dimethyl sulfide

acetate, CO2oxidation

cometabolism

oxidation

CarbonTetrachloride (CT) CO2denitrification

Reduction/co-metabolism/sulfate-reduction

acetogenesis

denitrification

acetogenesis

In presence of sulfide


CO2

Aerobic Conditions

Biological Transformations

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No associated notes

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Geochemical Elements Important to ISB

A decrease in nitrate, relative to background, may indicate that nitrate is serving as an electron acceptor under slightly reducing conditions.

Nitrate/nitrite (total)

An increase in dissolve Fe, relative to background, may indicate that Fe (III) is serving as an electron acceptor in anaerobic biodegradation.Iron (dissolved)

An increase in dissolve manganese, relative to background, (Mn[II]) may indicate that Mn(IV) is serving as an electron acceptor in anaerobic biodegradation.

Manganese (dissolved)

O2 is a microbial electron acceptor and a redox indicator. High oxygen (>2 mg/l) shows aerobic conditions and O2 will be the preferred electron acceptor until depleted.

Dissolved Oxygen

Used as a conservative tracer; for R-CL an increase in Cl may indicate reductive dechlorination.Chloride

CO2 and CO3/HCO3 are produced by microbial respiration, and an increase in alkalinity may indicate microbial growth from CO2 or organic acid production that lowers the pH and solubilizes carbonate.

Alkalinity

Reason for AnalysisPrimary Analytes for Groundwater

No associated notes

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Geochemical Elements Important to ISB

TOC may serve as electron donors and help to determine theamount of electron donor amendment required for Biodegradation

TOC may increase retardation of the COC due to sorption.

Total organiccarbon

An increase in methane, relative to background, may be anindicator of reducing conditions or microbial by-product usingcarbon dioxide as an electron acceptor.

• It is generally not present at most sites.

Methane

A decrease in sulfate, relative to background, may indicate thatsulfate is serving as an electron acceptor under anaerobicconditions.

• If this is the case, should be able to measure an increase in sulfides.

Sulfate

Measurement of reducing or oxidizing environment may be indicative of potentialbiological activity

Oxidation ReductionPotential (ORP) (mv)

Nutrient needed for microbial growth.Phosphate may need to be added to promote biodegradation.

Phosphate as P(soluble)

Optimum range 5 to 9 for ISBpH

REASON FOR ANALYSISPRIMARYANALYTES FORGROUNDWATER

No associated notes

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22Idealized Terminal Electron Acceptor ProcessGroundwater

+ Substrate

+800

ORP(mV)

-250

Perchlorate Reduction

Denitrification

Methanogenesis

Aerobic Respiration

Sulfate Reduction

Reductive Dechlorination

CO2 CH4

O2 H2O

NO3- N2

ClO4- Cl-

SO4-- HS-

CCl4 Cl-

Microbiologychemistryhydrogeologyengineering

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Receptors

Determine type and location

Determine exposure/impact

Mitigate exposure/impact (including use of ISB)

No associated notes

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Advantages & Limitations

Potential to remediate a site faster than with conventional technologies

Relatively lower cost of treatment compared to excavation and disposal, ex situ treatment or conventional pump-and-treat systems

Biofouling of amendment injection wells or points may be a challenge

Reduced risk of human exposure to contaminated media, compared to ex situ technologies

Enhanced technologies, when needed, may be costly or their implementation may be technologically challenging

Reduced potential for cross-media transfer of contaminants commonly associated with ex situ treatment

Specific contaminants or contaminant mixture at a site may not be amenable to ISB

Generation of relatively small amounts of remediation wastes, compared to ex situ technologies

A perceived lack of knowledge about biodegradation mechanisms

Capability to degrade chlorinated aliphatic hydrocarbons to relatively less toxic products

LIMITATIONSADVANTAGES

No associated notes

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25Systematic Approach to In Situ Bioremediation for Nitrates in Ground Water

Not a new Science

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The Environmental Nitrogen Cycle

AtmosphericNitrogen

Organic nitrogen

Ammonium

NitrogenFixation

Nitrite

Nitrate

AmmonificationOxidation

Fertilizer

Nitrate Contamination

Water TableLeaching

Plant Uptake

Plant Decay

Animal &HumanWaste Industry

AtmosphericNitrogen

Ground WaterGround Water Nitrate Contamination

Oxidation

Denitrification

N2 Gas

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•Nitrate is a worldwide problem as a groundwater contaminant•Biological denitrification of groundwater is under development as a technology to address this problem•Maximum Contaminant Level (MCL) is 10 mg/L nitrate-N•U.S. EPA estimates MCL is exceeded in 2.4% of domestic wells in U.S.•Two major sources: over-fertilization and human & animal waste

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Nitrate Compound Properties

Solubility 70g/100g water @21ºC

Vapor Pressure (mmHg) Negligible

Will not adsorb to rock matrix/conservative species

Very stable in groundwater

Requires bacteria to catalyze the conversion to nitrogen gas

Nitrate is most oxidized state of nitrogen

No associated notes

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0 2 4 6 8 10 12 14-1.0

-0.5

0

0.5

1.0

1.5

pH

Eh

(V)

NH4+

NH3

N2 (gas)

NO3-

NO2-

HNO2

N2 (gas)

PO2 = 1 bar

PH2 = 1 bar Sulfate-Sulfide Boundary

Eh-pH fieldof most

ground waters

Eh-pH

No associated notes

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Essential Parameters

• TOC analysis will indicate availability of naturally occurring carbon sources (e¯ donor).

Total Organic Carbon

• For EISBD (Enhanced In Situ Biodenitrification) to occur effectively, P needs to be available for microbial metabolism

Phosphorous (P)

• If dissolved manganese is present, indicates Redox is too low and matrix Mn/Fe is serving as e¯ acceptor.

Dissolved Manganese and Iron

• Redox will indicate which parameter serves as an electron acceptor

• Nitrate will be e¯ acceptor near ORP of 750 mv

Redox

• For EISBD to occur effectively, pH ranges can vary considerably (6.0 – 8.5)

pH

• For Enhanced In Situ Biodenitrification to occur, DO concentrations must be suppressed (<2 mg/l).

Dissolved Oxygen

• Due to microbial respiration production of CO2, can expect an increase in alkalinity from background.

Alkalinity

• You can expect a decrease in concentration if bioremediationis occurring

Nitrate/nitrite

REASON FOR ANALYSISPRIMARY ANALYTE

EISBD = Enhanced In Situ Biodenitrification

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Nitrogen Transformation Reactions

RNH2 + H2 NH4+ + energy (ammonification)

2NH4+ + 3O2 2NO2

- + 2H2O + 4H + energy2NO2

- + O2 2NO3- + energy (nitrification)

*R signifies an organic compound

Nitrate Generating Reactions

5C + 4 NO3- + 2H2O 2N2 + 4HCO3

- + CO2

Denitrification Reaction

NO3 → NO2 → NO → N2O → N2

Nitrate Degradation sequence

No associated notes

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Stoichiometric Ratios

2.55 mg of sucrosesucrose

1.37 mg of ethanolethanol

2.64 mg of acetateacetate

1.91 mg of methanolmethanol

Consumed C Amendment indenitrifying 1 mg NO3-NChemical

No associated notes

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Biologically Accelerated Denitrification

0 1 2 3 4 5 6 7 8Time (days)

0

100

200

300

400

500

Acetate

Nitrate

Nitrite

Nitr

ate

Con

cent

ratio

ns (m

g/l)

To convert the numbers above to Nitrate Nitrogen values divide the number by 4.4

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33Enhanced In Situ Biodenitrificationat field scale

Demonstration - Technical effectiveness of in situ denitrification for an active amendment delivery systemLocation -Albuquerque’s.• 40-year old nitrate plume covers 550 acres with a

volume of 1.69 billion gallons (6.4 billion liters)Cause - Over fertilization on a vegetable farm in the 1950sInformation - Water table is 72 ft (22 m) below ground surface, top 32 ft (10 m) of the saturated zone are contaminated with 90-500 mg/L of nitratesHealth - Near this site in 1980, a Blue Baby Syndrome incident was due to this plume• Demonstration by the NM Environment Dept & University

of NM

Abstract. The purpose of this demonstration is to evaluate the technical effectiveness of in situ denitrification for an active amendment delivery system (inverted 5-spot recirculating well pattern).The University of New Mexico teaming, with the New Mexico Environmental Department designed, constructed, and tested an inverted 5-spot recirculating well pattern denitrification system at the Mt. View site located in Albuquerque’s So. Valley. In this treatment pattern, water is pumped from each of the four corner wells and then re-injected following metered addition of a carbon source amendment into a center well. In this rather stagnate plume (nitrate contamination has been present for over 40 years) it is necessary to deploy an active pumping system to mix the carbon source with the contaminated groundwater.

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Injection of sodium acetate (NaAc) Amendment into the contaminated ground water

Consumption of NaAc by indigenous bacteria as an energy source

Reduction of nitrate into nitrogen gas by bacteria

Oxidize acetate to CO2

Steps in Biodenitrification

No associated notes

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Denitrification Reactions

Metabolic reaction:

0.625 Ac + NO3 → 1.25 HCO3 + 0.5 N2

Cell synthesis reaction:

3.5 Ac + NO3 → C5H7O2N + 2 HCO3

Combined reaction:

97% metabolic + 3% cell synthesis

0.712 Ac + NO3 → 0.485 N2 + 0.03 C5H7O2N + 1.273 HCO3

C5 H7 O2 N represents the chemical composition of cellular material

Ac represents Acetate (CH COO-)

No associated notes

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Design/Operating Parameters

Active amendment delivery system and mixing of nutrients with ground waterRecirculating injection of nutrient-amended water into aquiferFour extraction wells at corners of square grid pattern (100 ft.x 100 ft.) (30.5 x 30.5 m), one center re-injection well, all screened from 42-65 ft (12.8 – 19.8 m).Two in situ flow meters• Within 5 spot near injection well, depth at ~50 ft. (15.2 m)• Downgradient of system, depth at ~50 ft (15.2 m).

Total of 80,000 gallons of amended water from 4 wells re-injected into aquifer at a flow rate of 5 gal/minAmendment tank volume 200 gal, flow rate of 250 ml/min, injected and mixed directly in underground piping systemSodium acetate - 99.5 g/l, trimetaphosphate - 1.45 g/l

No associated notes

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37Inverted 5-Spot Amendment Delivery System

Monitoring Wells

Injection Well

Extraction Wells (4)

1 In SituFlow MeterPum

ped W

ater

View from above

*Continuous Denitrification

*Increases Water Movement

*Water movement can be monitored by in situ flow meters

No associated notes

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38Inverted 5 Spot Pattern Demonstrationat South Valley, New Mexico

No associated notes

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39Monitoring and Analytical Methods for Inverted 5 Spot Pattern

Monitoring wells• shallow (~50 ft.) (15.2 m)• deep (~65 ft.), (19.8 m)• analyzed at 8, 23, 29 and 64 days post-treatment

Bromide Tracer injected and measured with Ion Selective ElectrodeNitrate and nitrite measured with Ion Chromatograph

No associated notes

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In Situ Flow Meter (3-D) Warmer temperatures recorded on down stream side of flow sensorMeasured velocities from .01 to 2 ft/dayBefore pumping (0.1ft/day)After pumping (1.2 ft/day)

No associated notes

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1197

013

285

15

518

60 72

Nitrate Nitrite

Con

cent

ratio

n,pp

m BeforeTreatment

8 Days AfterTreatment



Nitrate and Nitrite concentrations, as NO3, before and after treatment (Shallow Well)

No associated notes

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0

405

221

25

111

2.6

Nitrate Nitrite

Con

cent

ratio

n,pp

m BeforeTreatment




Nitrate and Nitrite concentrations, as NO3,before and after treatment (Deep Well)

No associated notes

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SuccessesLarge-scale in situ bioremediation system for nitrate-contaminated ground water plume was successful• Reduced nitrate concentration below 10 mg/l• Approximately 450 Kg (1000 lbs) of nitrate were converted to

nitrogen gas• Inverted 5-spot pattern provided good mixing, wide aerial

sweep & easy operation.Challenges

Biofouling of the injection well • Common to most ISB systems• Control measure should be incorporated• Will increases project costs

Assure nitrite reduction goes to completionIn the future, biofouling control measures will be incorporated into active system

Conclusions

No associated notes

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Questions & Answers

???

The ITRC Document: “Systematic Approach to In SituBioremediation in Groundwater: including Decision Trees on Nitrate, Carbon Tetrachloride and Perchlorate” is downloadable in the links page at the end of today’s presentation.

No Associated Notes

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45Systematic Approach to In Situ Bioremediation of Carbon Tetrachloride in Ground Water

Not a new Science

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Carbon Tetrachloride Pervasiveness

Found at 22% of Superfund sitesHistoric grain silo sites Found at chlorinated solvent releasesFound at DOE facilities

Please refer to Sections 9.2.1, 9.2.2, and 9.2.5 of the Guidance document

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47Carbon Tetrachloride Sources of Contamination

These previous uses of Carbon Tetrachloride resulted in contamination:Past use to make refrigerantsPropellants in aerosol cansUsed in fire extinguishersPast use as a grain storage fumigantCleaning fluidCold War use to recover plutonium


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Degradation Products and Properties

2,103435197115Vapor Pressure (mmHg)

1.82.934.125.32Vapor Density (Air=1)

-97.6 ºC-95 ºC-63.2 ºC-23 ºCMelting Point

-24.2 ºC39.75 ºC61.2 ºC76.8 ºCBoiling Point

1.27 x 10-23.25 x 10-33.67 x 10-32.76 x 10-2Henry’s Law Constantatm-cu meter/mole @

25 ºC

6,50013,0007,710 C793Water Solubilitymg/L @ 25 ºC

62131110Partition Coefficient (KOC)

0.921.32551.48351.5940Density/SpecificGravity @ 20 ºC

50.4984.93119.38153.82Molecular weight

CM(CH3CL)

DCM(CH2Cl2)

CF (CHCl3 )

CT(CCl4)

Property

Please refer to Table 9-1 of the Guidance document for a more complete table.

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Contaminant Relationships

Degradation products• CF, DCM, CM

Petroleum hydrocarbonsNitrateGrain fumigant• “80-20” (CT and carbon disulfide)• “70-30” (DCA and CT)• Organophosphate pesticides• Chloropicrin (Cl3CNO2)• EDB


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50Chlorinated Methanes Degradation Pathways

Chloroform(CF)

Dichloromethane(DCM)

Chloromethane(CM)

Aerobic Conditions Anaerobic Conditions


Methane(CH4)



CO2, CO, CSO, CS2

acetate, formic acid

CO2

methanethiol dimethyl sulfide

acetate, CO2oxidation

cometabolism

oxidation

CarbonTetrachloride (CT) CO2denitrification

Reduction/co-metabolism/sulfate-reduction

acetogenesis

denitrification

acetogenesis

In presence of sulfide


CO2

Please refer to Figure 9-4 of the Guidance Document

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Direct Reductive Dechlorination of CT

Bacteria Halorespire CT that serves as an electron acceptorTwo electrons are transferred at each step (source of energy for bacteria)CT sequentially reduces and looses a Cl ion during each stepCT CF DCM CM CH4

Please refer to section 9.3.3.1 and Figure 9-1 (Reductive Dechlorination Decision Tree) of the guidance document.

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52Idealized Sequence of Direct Reduction of Chlorinated Methanes

REDUCTIVE DECHLORINATION OF CT

CT CF DCM CM

Distance from Source

Con

cent

ratio

n

No associated notes

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Anaerobic Cometabolism

Cometabolic Reductive Dechlorination• CT is fortuitously degraded by enzymes or

cofactors and degradation products appear

Cometabolic Denitrification• Occurs under denitrifying conditions• Results in little to no production of CF• Requires a greater management of an enhanced

ISB system

Please refer to sections 9.3.3.2 through 9.3.3.4 and Figure 9-2 (Cometabolic Denitrification Decision Tree) of the guidance document.

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Case Study – Cometabolic Denitrification

Schoolcraft, Michigan CT plumeFull scale ISB project implemented to treat plume at leading edgeBioaugmentation of Pseudomonas stutzeri KCRow of extraction and injection wells to create a biocurtain forcontaminant interception and destructionSuccessfully removed CT and NO3

http://www.egr.msu.edu/schoolcraft/story/html

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Case Study – Cometabolic Denitrification

200 Area at Hanford DOE (Central Plateau)Possibly 600,000 Kg of CT entered soil columnISB demonstration between 1995-1996CT ~ 2 mg/l, NO3 ~ 250 mg/lGW extracted, nutrients added, re-injectedApproximately 2 Kg of CT destroyed with little CF production

http://apps.em.doe.gov/ost/pubs/itsrs/itsr1742.pdf

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56Case Study –Cometabolic Reductive Dechlorination

Grain silo in Tucumcari, NMDiscovered while conducting a LUST investigation, plumes comingledNO3 background of 20 mg/l NO3-NGasoline served as electron donorObserved degradation products of CTObserved cometabolic denitrification

http://www.nmenv.state.nm.us/gwb/intricom/html

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Fate and Transport

Since there are many competing pathways catalyzed by different bacteria, there is no simple stoichiometric equation.Reductive Dechlorination Pathway is straightforward.

2(CCl4) + 3(C3H5NaO3) + 13 (OH-) 3Na+ + 8 Cl- + 11CO2 + 28 H+

Please refer to section 9.4 of the guidance document.

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This CoC is expected to decrease in concentration if bioremediation is occurring. Also, if this electron acceptor becomes depleted, carbon tetrachloride may reductively dechlorinate creating degradation products.

Nitrate/nitrite

An increase in chloride concentration from background may indicate a reductive dechlorination of carbon tetrachloride.

Chloride

This CoC is a degradation product of reductive dechlorination of carbon tetrachloride

CM


DCM


CF

Decreases in concentration if ISB is occurringCT


No associated notes

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Essential Parameters Cont’d

This constituent may be present as the final degradation product of carbon tetrachloride dechlorination or may be present if ORP conditions are so low that methanogenesis is occurring.

Methane

TOC analysis will indicate availability of naturally occurring carbon sources (e¯donor).


For ISB of carbon tetrachloride to occur effectively, sufficient P needs to be available for microbial metabolism. (P may need to be added as an amendment)

Phosphorous (P)

If sulfide (H2S) concentrations are greater than background, sulfate may be serving as an electron acceptor producing sulfides.

Sulfide

If sulfate concentrations are less than background and ORP is low, sulfate may be serving as an electron acceptor and reduction may be occurring.

Sulfate

If dissolved manganese or iron is present, indicates ORP is too low and matrix Mn/Fe is serving as e- acceptor.

Dissolved Mn and Iron


No associated notes

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Essential Field Parameters

The ORP may be used in conjunction with electron acceptor concentrations as a qualitative indicator of ORP conditions and in identifying which electron acceptor(s) may be active.

ORP

ISB of carbon tetrachloride occurs effectively in wide pH ranges (5.5-9.5).

pH

For ISB of carbon tetrachloride to occur, DO concentrations must be depleted (<2 mg/l).

Dissolved Oxygen (DO)

Due to microbial respiration production of CO2, you can expect an increase in alkalinity from background.

AlkalinityREASON FOR ANALYSISPRIMARY ANALYTE

No associated notes

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Regulatory Standards

Water Quality Control Commission (5 CCR 1002-41)

CT– 0.27CF – 6DCM – 4.7CM – no numeric standard

Colorado

Uses Safe Drinking Water Act, part 141, title 40 CFR. Virginia

CT– 5CF – no numeric standardDCM – 5CM – no numeric standard

Arizona

New Hampshire Groundwater Management and Groundwater Release Detection Permits Env-Wm 1403

CT – 5CF – 6DCM – 5CM – 3

New Hampshire

New Mexico Water Quality Control Commission Regulation 20.6.2.3103 NMAC

CT – 10CF – 100DCM – 100CM – no numeric standard

New Mexico

State RegulationNumeric Standards (µg/L)State

No associated notes

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Regulatory Standards (cont’d)

3003CM

3003DCM

10,000100CF

5005CT

TDS > 2,500TDS ≤ 2,500 Pennsylvania Land Recycling Program Regulations Subchapter C, §250.304 and §250.305

Used AquifersUsed Aquifers

Pennsylvania

Standards of Quality for Waters of the state Chapter 33-16-02, ND Adm Code

CT- 5CF - 100 MCL or HALDCM- 5CM- 3

North Dakota

Oklahoma Standard for Groundwater Protection and Corrective ActionSubchapter 7, §785:45-7-2

CT– 4CF – 10DCM – no numeric standardCM – 2.7

Oklahoma

No numeric standardCM

1507151DCM

110.8CF

532CT RSMo §260.565 -260.575 and administrative rule 10 CFR 25-15.010

Scenario CScenario BScenario A

Missouri

State RegulationNumeric Standards (µg/L)State

No associated notes

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Challenges of CT ISB Systems

Determining the reductive pathway most suitable for your site• Characterization• Lab scale treatability tests• Pilot scale field demonstrations

Biofouling and amendment mixingRegulatory concerns

Please refer to sections 9.4.3, 9.5, and 9.6 of the guidance document for the above bullets, respectively.

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64Systematic Approach to In Situ Bioremediation of Perchlorate in Ground Water

Not a new Science

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Perchlorate

Realization of widespread contamination in the US since 1997, following development of low level analytical method (ppb).

Human health concerns centered on thyroid gland effects

EPA derived RfD of 1 µg/L, but toxicological studies are ongoing.

Ecological studies also ongoing but exposure pathways still not well known.

No associated notes

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Perchlorate Sources

Contamination originates when perchlorate salts (ammonium, potassium, magnesium, sodium) dissolve in ground and surface watersAmmonium salt used as solid propellant for rockets, missiles, and fireworks Used in munitions, explosivesNumerous industrial uses (airbag inflators, nuclear reactors, electroplating, paint manufacture, etc.)Rare natural occurrences

Please refer to sections 10.2 and 10.3

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Perchlorate Pervasiveness

Reported Facilities

No Known Facilities

Manufacturers and Users

(at least 44 states)Environmental

Releases

Reported Releases

No Known Releases

Please refer to Sections 10.2 and 10.3

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Properties of Perchlorate Ion

Not volatile Highly solubleDoes not adsorb strongly to surfaces (negatively charged ion)Stable in ground water environmentsNot readily reduced due to kinetic barriers

Please refer to section 10.3.2 and table 10-1

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Contaminant Relationships

Degradation Products: • Chlorate (ClO3

-)• Chlorite (ClO2

-)• Chloride (Cl-)

Co-contaminants include:• Nitrate• Sulfate • VOCs• Nitroaromatic explosives (TNT, HMX, RDX)

Please refer to section 10.3.3

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Perchlorate Reduction Pathway

ClOClO44-- ClOClO33

-- ClOClO22-- ClCl-- + O2

PerchloratePerchlorate ChlorateChlorate ChloriteChlorite ChlorideChloride

Oxidation

State: (+7)(+7) (+5)(+5) (+3)(+3) ((--1)1)

CH2O

CO2H2O

CH2O

CO2H2O

CO2H2O

CH2O

Progressive reduction in oxidation state of chlorine atom through loss of oxygen atomsPlease refer to section 10.5.3

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71Idealized Sequence of Terminal Electron Accepting Processes (TEAPs)

Perchlorate Reduction

Denitrification

Methanogenesis

Aerobic Respiration

Sulfate Reduction

Reductive Dechlorination

Groundwater+

Substrate

+800

ORP(mV)

-250CO2 CH4

O2 H2O

NO3- N2

ClO4- Cl-

SO4-- HS-

CCl4 Cl-

Microbiologychemistryhydrogeologyengineering

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Final degradation product of the reductive process.May be difficult to distinguish from background values.Chloride

Intermediate degradation product, may be indicative of perchlorate reduction, but may not be detected due to rapid reduction to chloride.

Chlorite

Intermediate degradation product, may be indicative of perchlorate reductionChlorate

Nitrate and nitrite may compete with perchlorate as electron acceptor

Nitrate + Nitrite

An adequate organic carbon source (electron donor) is needed forreductive degradation to occur.


Optimal range is 0 to 100 mV.If too low, sulfate reduction may be the dominant TEAP.If too high, Mn oxide or nitrate reduction may be dominant TEAPs.

ORP

Optimal range is 6.5 – 7.5pH

Low or absent for anaerobic conditionsDissolved Oxygen

Please refer to section 10.5 and table 10-4

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Current Perchlorate Regulatory GuidanceRemediation

(µg/L)Drinking Water

(µg/L)

144EPA Region 9

1.5EPA Region 1

4 to 18US EPA Guidance

4Texas

1818Nevada

5New York

1New Mexico

1.5Massachusetts

4California

14 (health based guide)

Arizona

Please refer to section 10.4 and table 10-3 for additional information and references.

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Ex-Situ Bioremediation of Perchlorate

Ex-situ Bioremediation of perchlorate is a proven technology:• Aerojet (N. CA)

4 full-scale bioreactors operating since 19982,500 µg/L consistently reduced to <4 µg/L

• San Gabriel Superfund Site (CA)• Tyndall AFB (FL)• Thiokol (UT)• Longhorn Ammunition Plant (TX)• NWIRP (McGregor, TX)


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In-Situ Bioremediation of Perchlorate

In-situ bioremediation of perchlorate is an emerging technologyLaboratory-scale studies, R&D• Penn State University, Southern Illinois University,

Envirogen, GeoSyntecField Demonstrations• Aerojet (San Gabriel, CA)• Edwards AFB (CA)

Biobarrier (immobile C source)• NWIRP ( McGregor, TX)• Baldwin Park OU, (San Gabriel, CA)


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76Technology Status/Future Needs of ISB for Perchlorate

Wide variety of potentially suitable electron donors for enhancing halorespiration (compost, mulch, vegetable oil, sugars, alcohols, lactate, acetate, etc.)ISB may be implemented through liquid phase injection or in biobarriersFew in-situ field applications have been completed, but more studies are underwayDue to emerging nature of ISB, will require treatability testing and pilot-scale field demonstration on a site-specific basis

Please refer to sections 10.6.3 to 10.6.5

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In Summary

Not a new Science

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In Situ Bioremediation Issues

Regulatory• RCRA 3020 (b)• Underground Injection Control• Contaminant Specific Issues

Biofouling (Section 4.4.7)Amendment Mixing (Section 4.4.8)

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UIC Regulatory Variables

Colorado defers to UIC under USEPAAlthough ISB is regarded as std. remediationtool

NANANAColorado

Class III MineralResources Injection Or Production WellOperating Permits

Clean WaterAct, 10 CSR206

Missouri

Regulates ISB under each program likehazardous waste, surface water, and otherremediation programs. Allows injection onlyFor the purpose of remediation.

Virginia

ISB wells are permitted by rule if part of a remediation projectSections 16, 17 & 18

Underground Injection Control Program, Chapter 33-25-01 NDAC

NorthDakota

Pollution Prevention Permits (DischargePlans) are issued for injection ofamendments

DraftMNA

Water Quality Control

CommissionRegulations20.6.2 NMAC

Water QualityAct, Chapter74, Article 6NMSA 1978

New Mexico

COMMENTS POLICYREGULATIONSTATUTESTATE

No associated notes

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Bottom line for ISB

Reductions(electron acceptors)

SO4 = to HS-

Fe++ to Fe(OH)3

CO2 to CH4H+ to H2

H2 to H+

EDB to EHCA to PCE

O2 to H2ONO3

- to N2

CT to CFPCE to TCE

CF to MC

TCA to 1,1-DCATCE to DCE

1,1-DCA to CANO3

- to NO2-

DCE to VC

0 +50 +100-50

0 +0.5 +1.0-0.5

0 +5 +15-5 +10pE'

E°' (V)

Free Energy (kJ/mol of electrons transferred

NADH to NAD+

Vitamin B-12 (reduced to oxidized)Acetate to CO2

Oxidations (electron donors) Hydrogenolysis

favorable

Dichloro-elimination

favorable

Reductions(electron acceptors)

SO4 = to HS-

Fe++ to Fe(OH)3

CO2 to CH4H+ to H2

H2 to H+

EDB to EHCA to PCE

O2 to H2ONO3

- to N2

CT to CFPCE to TCE

CF to MC

TCA to 1,1-DCATCE to DCE

1,1-DCA to CANO3

- to NO2-

DCE to VC

0 +50 +100-50

0 +0.5 +1.0-0.5

0 +5 +15-5 +10pE'

E°' (V)

Free Energy (kJ/mol of electrons transferred

NADH to NAD+

Vitamin B-12 (reduced to oxidized)Acetate to CO2

Oxidations (electron donors)

Oxidations (electron donors) Hydrogenolysis

favorable

Dichloro-elimination

favorable

No associated notes

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Bottom line for ISB

Understand subsurface hydro-geological regime (i.e. flow and transport)

Understand contaminants (properties and fate)

Create conditions conducive to biodegradation (substrates)

Assure transforming microbes are present

Touch ALL regulatory bases

Implement ISB!!

No associated notes

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Questions & Answers

Thank you for participating in ITRC Internet Training. To get more information on ITRC – Go to www.itrcweb.org

CCl4

CHCl3

CH2Cl2

CH3ClCH4

No associated notes

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Thank you for your participation

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ResourcesResourcesToTo

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